A liquid crystal display panel generally has a pair of transparent substrates opposed to each other, and a liquid crystal portion composed of liquid crystal molecules disposed between the pair of substrates. An inner surface of each of the substrates has an alignment layer which is alignment-treated to provide a predetermined alignment direction of the liquid crystal molecules. The alignment treatment of each of the substrates is performed by using a rubbing device. The rubbing device has a rubbing roller for rubbing the surfaces of the substrates before assembling the substrates into a liquid crystal display panel. The rubbing roller has a rubbing cloth stuck on a roller base.
When the rubbing cloth is stuck on the roller base, there always exists a seam between opposing edges of the rubbing cloth. In case the substrates are rubbed by using such rubbing roller, alignment direction becomes uneven in some or all portions of areas where the seam of the rubbing cloth contacts the substrate. Therefore, display unevenness or defect of the liquid crystal display panel occurs.
In order to obviate such disadvantage, it may be possible, as a first method and as shown in FIG. 4, to make a seam or gap 104 between the opposing edges of a rubbing cloth 102 as narrow as possible, by controlling the length of the rubbing cloth 102 along the circumference of a roller base 101. By fabricating a rubbing roller in this way, the width of the seam 104 can be approximately zero, and an influence of the seam 104 can be reduced.
As a second method and as shown in FIG. 5, it is also possible to separate a rubbing cloth into a plurality of oblong rubbing cloth members 202 and to stick the members onto the surface of a roller base 201 such that each gap (or seam) 204 between adjacent rubbing cloth members 202 becomes as narrow as possible and such that a plurality of seams 204 are produced. Thereby, all portions of the surface of the alignment layer coated on the substrate of a liquid crystal display panel to be rubbed contact the seam or seams 204, and it is possible to uniformly rub the alignment layer.
However, in the above-mentioned first method, it is necessary to precisely control the length of the rubbing cloth 102 along the circumference of a roller base 101 and to stick the rubbing cloth 102 precisely on the roller base such that the seam or gap 104 between the opposing edges of a rubbing cloth 102 can be as narrow as possible, taking the expansion and contraction caused by the temperature variation and the like into consideration. Therefore, it is usually very difficult to precisely control the length of the rubbing cloth 102 and to precisely stick the rubbing cloth 102 on the roller base 101.
Also, in the above-mentioned second method, it is also necessary to precisely control the length of the rubbing cloth members 202 along the circumference of a roller base 101 and to stick the rubbing cloth members 202 precisely on the roller base such that the gaps between the opposing edges of the rubbing cloth members become as narrow as possible or such that the gaps between the opposing edges of the rubbing cloth members are precisely controlled, taking the expansion and contraction caused by the temperature variation and the like into consideration. It is usually very difficult to precisely stick the rubbing cloth members 202 on the roller base 201 such that the gaps between the rubbing cloth members are precisely controlled. Also, the process of sticking a plurality of separate rubbing cloth members on the roller base requires close attention, becomes complicated and takes a long time.